炭化三维间隔棉织物的制备及其电加热性能

Preparation of carbonized three-dimensional spacer cotton fabric and its electrical heating properties

为开发一种结构稳定可应用于压阻传感和电加热的功能型纺织品,研制出一种机织三维间隔织物基体,通过在惰性气体高温环境制备炭化三维间隔棉织物,应用扫描电子显微镜、傅里叶红外光谱和拉曼光谱对制备炭化棉织物纤维结构进行表征,研究其电加热性能。结果表明:炭化三维间隔棉织物具有很好的导电性,可视为均匀的电阻介质,且电阻变化率随着织物炭化温度升高呈指数降低;在较低炭化温度情况下电阻变化率较大,随着炭化温度升高,电阻变化率逐步降低。通过对织物升温效果与加热性能分析可知,织物在低于62.4℃时,其理论加热效率与升温温度呈等比关系,可应用于温度精准可控的电加热织物。

Objective In order to develop functional textiles used in piezoresistive sensing and electric heating,the effects of different carbonization processes on the conductivity and electric heating properties of cotton fabrics were studied.Method Using cotton fiber as the raw material,a three-dimensional spacer fabric was prepared using a double-shed weaving machine.The fabric was then carbonized to achieve the conductive and heating properties.The fiber structure in the carbonized cotton fabric was characterized by scanning electron microscopy,Fourier infrared spectroscopy and Raman spectroscopy.The conductivity and electric heating performance of the fabric were characterized by multimeter and infrared thermal imager,and their internal relations were analyzed.Results The fabric can be carbonized by high temperature inert gas(N 2)(Fig.3).In the carbonization process,with the increase of carbonization temperature,the fiber scale layer structure was obvious seen,and the fiber surface structure became more porous.When the carbonization temperature of the fabric was set to 900℃,obvious punctate broken holes appeared on the fiber surface,and carbon particles falling off were observed.By analyzing the conductivity of the fabric,it was found that the resistance of the carbonized fabric decreased with the increase of carbonization temperature.The resistance of the charred fabric gradually increases with increasing measurement distance,the fabric resistance is linearly related to the plane distance and can be seen as similar to a uniform resistance.At a lower carbonization temperature or a higher current,the heating performance of the carbonized fabric is better,but there will be a lot of heat radiation and air heat exchange during the heating process of the fabric.The actual temperature rise curve of the fabric does not agree with the theoretical calculation of electric power(Fig.8).The carbonized fabric was found to be heated and cooled fastest at 750℃.When the heating temperature of the carbonized fabric was lower than 62.4℃,the heating temperature of the fabric demonstrated proportional increases to the value of the theoretical electric power(Fig.11).In the case where the heating temperature was higher than this temperature,the theoretical power of the fabric was significantly lower than the temperature of the fabric.Conclusion The three-dimensional space carbonized cotton fabric demonstrated good electrical conductivity and it can be regarded as a uniform resistance medium,and the resistance rate decreases exponentially with the increase of carbonization temperature.At lower carbonization temperature,the change rate of resistance is larger,and with the increase of carbonization temperature,the change rate of resistance gradually decreases.Through the analysis of the heating effect and the heating property of the fabric,it is found that the theoretical heating efficiency of the fabric is proportional to the heating temperature when the temperature is below 62.4℃,and it can be applied to the electrically heated fabric with precise and controllable temperature.